An important and continuing goal in the data storage industry is that of increasing the density of data stored on a medium. For tape storage systems, that goal has lead to increasing the track density in recording heads, and decreasing the thickness of the magnetic tape medium. However, the development of small footprint, higher performance tape drive systems has created various problems in the design of a tape head contour for use in such systems.
First, as is well known in the art, data storage efficiency can be reduced by entrained air causing separation between a magnetic tape and a recording head as the tape moves over the head. Such separation losses can be reduced by providing bleed slots in the head typically extending in the direction of tape travel. To adequately eliminate entrained air at higher tape speeds, the length of such slots must increase and the island widths between those slots must decrease. However, at higher tape speeds and with thinner tapes, air can still become entrained between the tape and the slot islands, thereby causing separation losses and a degradation of performance.
Moreover, for higher tape speeds, the slots must be made wider, and the slot islands therefore narrower, in order to adequately defeat entrained air. The narrower the slot islands, the more difficult they are to manufacture and the more prone they are to breakage. Additionally, as is well known in the art, in order to increase the amount of data recorded on the tape, the head may move laterally to write to and read from additional tracks on the tape. As the head moves, the slot islands can become entangled with the tape.
As is also well known in the art, in a multi-gap tape head where the read and write elements are located in adjacent gap lines, as the element width decreases, the spacing between adjacent gap lines must decrease in order to reduce/minimize azimuth alignment errors. By decreasing such "gap-to-gap" spacing, however, less space is available for placement of bleed slots having sufficient length to adequately prevent separation losses. This problem is compounded as tape speeds are increased.
It is still further well known in the art that head performance can also be affected by an improper angle at which the tape is presented to the tape head. That is, if the tape angle becomes too large or too small, the tape will not adequately contact the head, resulting in increased head to tape separation and thereby degrading performance. Conventional high performance tape drive systems have utilized precision tape paths that are part of the drive and to which the recording head is precisely aligned during manufacturing to ensure proper wrap of the tape head.
Tape storage systems, however, are increasingly using tape cartridges into which the tape head must be inserted in order to read from or write to the tape. In this case, the tape path is contained in the cartridge while the head is located in the tape drive. Such cartridges therefore introduce the problem of much greater variations in tape wrap. One solution to this problem has been to provide a tape head assembly with a stabilizer or outrigger on each end thereof to set the tape wrap on the tape head such that the tape engages the head properly.
However, the process for manufacturing a multi-gap tape head assembly requires high precision and is very time-consuming. Therefore, the addition of such stabilizers to a tape head assembly increases both the complexity and the cost of the assembly. Such stabilizers also increase the size of the assembly, which can present an additional problem given the limited size of the opening in the tape cartridges into with the tape head must be inserted.
Thus, there exists a need for a multi-gap tape head having a contour that would prevent separation losses while providing for the reduced gap-to-gap spacing required in a tape head assembly used for high density recording. Such a contour would also adequately compensate for tape wrap angle variations in tape cartridge applications, and minimize the complexity of the resulting tape head assembly.